I have noticed this funny trend with my wrist, which I had my third surgery on after breaking it and tearing it before summer last year. The pain almost always starts to increase as I get close to the end of an activity. If you don’t think too much about this it makes perfect sense. My wrist gets tired and my barriers drop as I do things. But I noticed that it didn’t seem to increase at a constant rate, it seems relative to how much longer I need to survive doing something: as I get closer to the end the pain increases, often at an extremely fast rate.
My first thought is what does that say about how much pain I’m actually in? But then I got to thinking about sports and how how bodies do a very similar thing. When I run 5 km I’m tired at the end, my legs are burning and I feel like I have to stop or I will run out of air. When I run 10 km I’m tired at the end, etc. In fact I feel about as tired as when I run the 5 km. That makes sense right, I mean I must run faster during the 5 km but longer during the 10 km, but that isn’t what my race times say. My 10 km is almost exactly double my 5 km. Now, disclaimer here, I run recreationally among all my other sports, so perhaps it’s different for trained runners.
Baden, Warwick-Evans, and Lakomy (2004) studied the impact of running duration on rate of perceived effort (RPE) and the relationship between RPE and what runners were thinking about. What they found was, when pace is kept constant, runners consistently report higher RPE over the entire duration of short runs compared to longer runs. In other words, they think they are working harder throughout the shorter runs. This seemed to be correlated with how often they were thinking about how their body was feeling, compared to unrelated thoughts such as thinking about the environment they are passing through: they thought more about their body (associative thoughts) on short runs, and more about other things (dissociative thoughts) on long runs. (Both run distances were long enough to be primarily within the same energy system).
The researchers suggest a possible mechanism for this finding. Other researchers have found that there seems to be a limited amount of attention, with dissociative thoughts other things are occupying your attention, which reduces how much of your physical discomfort you can actually register.
So how does this relate to my experience of my pain and how does it affect ability to train?
As I get closer to the end of whatever I’m doing, less and less of my brain is focused on the something else, opening more pathways to register my pain. So while there could be similar levels of pain throughout, I don’t pay attention until the end, so my perception is that I hurt more at the end no matter the length of the activity.
In training, I found I needed to get to a happy place, when I knew I could perform for the distance/time required. Once I got to that point, it was easier to think about things other than how tired I was getting or how much my muscles were burning. Now the trick is being able to think about my body and my technique without associating those thoughts with how tired I’m getting. Then, I should be able to perform at a more consistent and higher level no matter the distance.